fix(hub): ship checklist via cph_hub todo_write MCP tool

Native Claude TodoWrite is not registered in headless agent mode even with
--tools default. Add mcp__cph_hub__todo_write (always enabled), mirror the
TodoWrite schema, instruct multi-step runs to use it, and keep the Feishu
progress panel parsing both native and hub tool names.

hub/src/feishu/card/builder.ts

@@ -43,6 +43,7 @@ const TOOL_ICONS: Record<string, string> = {
   grep: "search-filled",
   edit: "edit-filled",
   todowrite: "todo-filled",
+  todo_write: "todo-filled",
   send_file: "send-filled",
   request_approval: "thumb-up-filled",
   feishu_read_context: "search-filled",
@@ -52,10 +53,20 @@ const TOOL_ICONS: Record<string, string> = {
 };
 
 function toolIcon(toolName: string): string {
-  const normalized = toolName.toLowerCase().replace(/^mcp_/, "");
+  const normalized = toolName.toLowerCase().replace(/^mcp_/, "").replace(/^cph_hub__/, "");
   return TOOL_ICONS[normalized] ?? "tool-filled";
 }
 
+function isTodoToolName(toolName: string): boolean {
+  const lower = toolName.toLowerCase();
+  return (
+    lower === "todowrite" ||
+    lower === "todo_write" ||
+    lower.endsWith("__todo_write") ||
+    lower.endsWith("__todowrite")
+  );
+}
+
 // ---------------------------------------------------------------------------
 // Card builder
 // ---------------------------------------------------------------------------
@@ -80,8 +91,8 @@ export function buildAgentCard(params: {
     elements.push(buildTodoPanel(todos, phase !== "complete"));
   }
 
-  // Tool-use panel (exclude TodoWrite itself — already shown as checklist)
-  const visibleToolSteps = toolUseSteps.filter((step) => step.toolName.toLowerCase() !== "todowrite");
+  // Tool-use panel (exclude todo tools — already shown as checklist)
+  const visibleToolSteps = toolUseSteps.filter((step) => !isTodoToolName(step.toolName));
   if (visibleToolSteps.length > 0) {
     elements.push(buildToolUsePanel(visibleToolSteps, toolUseElapsedMs, phase !== "complete"));
   } else if (

hub/src/feishu/fileDeliveryTool.ts

@@ -399,6 +399,50 @@ export function createFileDeliveryMcpServer(options: FileDeliveryToolOptions): M
       );
     }
   }
+  if (enabledTools.has("todo_write")) {
+    tools.push(
+      tool(
+        "todo_write",
+        "Create or replace the shared task checklist for this run. Call this first when the user`s request has multiple steps, then again whenever progress changes. Each item needs content + status (pending|in_progress|completed). Optionally set activeForm (present-tense label) for the current in_progress item. Keep exactly one item in_progress when work is underway. Hub shows this list on the Feishu card so teachers can track progress.",
+        {
+          todos: z
+            .array(
+              z.object({
+                content: z.string().min(1).describe("Imperative task description, e.g. Search PBank for derivatives."),
+                status: z
+                  .enum(["pending", "in_progress", "completed"])
+                  .describe("pending | in_progress | completed"),
+                activeForm: z
+                  .string()
+                  .optional()
+                  .describe("Present continuous label while in_progress, e.g. Searching PBank."),
+              }),
+            )
+            .min(1)
+            .max(32)
+            .describe("Full replacement list for the checklist (not a patch)."),
+        },
+        async (args) => {
+          const completed = args.todos.filter((t) => t.status === "completed").length;
+          const inProgress = args.todos.filter((t) => t.status === "in_progress").length;
+          const lines = args.todos.map((t, i) => {
+            const mark = t.status === "completed" ? "x" : t.status === "in_progress" ? ">" : " ";
+            const label = t.status === "in_progress" && t.activeForm ? t.activeForm : t.content;
+            return `${i + 1}. [${mark}] ${label}`;
+          });
+          return {
+            content: [
+              {
+                type: "text",
+                text: `Checklist updated ${completed}/${args.todos.length} completed, ${inProgress} in progress.\n${lines.join("\n")}`,
+              },
+            ],
+          };
+        },
+        { alwaysLoad: true },
+      ),
+    );
+  }
 
   const instructions = mcpInstructions(enabledTools);
   return createSdkMcpServer({
@@ -507,6 +551,12 @@ function mcpInstructions(enabledTools: ReadonlySet<CphHubMcpToolId>): string {
       "If tools fail because no ACTIVE pbank capability connection exists, tell the user an org admin must configure 题库 on the admin capabilities page.",
     );
   }
+  if (enabledTools.has("todo_write")) {
+    instructions.push(
+      "For multi-step work, call todo_write first with a full checklist, then update it as each step starts/finishes so the teacher sees live progress on the card.",
+      "Prefer mcp__cph_hub__todo_write (todo_write) for progress tracking — do not skip it because built-in TodoWrite is absent.",
+    );
+  }
   instructions.push(
     "Role skill docs (when bound) are readable at .cph/runtime-skills/<skill-name>/SKILL.md or $CPH_RUNTIME_SKILLS_DIR/<skill-name>/SKILL.md. Prefer the Skill tool when available. Workspace .claude/ and .mcp.json are sandbox stubs — not skill or MCP source.",
   );